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| bio | website | |
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| age | ||
| visits | member for | 2 years, 6 months |
| seen | May 14 at 16:58 | |
| stats | profile views | 208 |
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May 7 |
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Preconditioning and effects on precision of solution of LSE I do not think that your answer makes sense. Preconditioning precisely means decreasing the condition number. So there is no 'balancing' necessary between error magnification and convergence rates. In particular, my question regards only the numerical level - it is about the stability of numerical algorithms. |
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Apr 5 |
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Boundedness of a Solution Operator @user17904: You need to show that for Sobolev space $H$ of sufficient regularity the trace from $H$ to $L^2(\partial\Omega)$ has closed range. Than a bounded right-inverse exists by functional analysis. Typically, you can prove surjectivity, say, by partition of unity, smoothing and an explicit construction. |
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Mar 7 |
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pseudoinverse under change of norm I have completely rewritten the question. |
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Mar 4 |
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An variation of “Lk” in simplicial complexes @StefanH.: Yes, thanks. |
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Feb 13 |
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How can not-equals be expressed as an inequality for a linear programming model It is intutive it does not work, because polyhedrons are convex and closed, while not-equals correspond to non-convex open regions. |
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Jan 29 |
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Approaches to integrate $\int_0^1 \frac{x}{\sqrt{a+bx+cx^2}} dx$ Thanks, that got me on the right track. |
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Jan 27 |
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If A $\subset S^n$ has spherical diameter < $\pi$, then $S^n - A$ contains a closed semisphere. The original statement was blatantly wrong. I have editted the question into what I actually meant. |
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Dec 19 |
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Distinction between 'adjoint' and 'formal adjoint' These lines on Wikipedia only describe the construction for a differential operator. I have been concerned about general operators and their formal adjoints. |
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Nov 2 |
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Solid angle between vectors in n-dimensional space Your second formula is quite awkward, because you apply arctan against a vector. |
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Jul 18 |
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Proof by Induction $n^2+n$ is even You know you don't need induction, do you? |
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Jul 11 |
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Minimizer of $p$-average of distances to points $x_1,\dots,x_n$ @ChristianBlatter: A name, like some exotic mean, would be helpful, of course. |
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Jul 11 |
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Minimizer of $p$-average of distances to points $x_1,\dots,x_n$ @Paul: Yes, by definition. The vector $D$ is just a formal device. |
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Apr 7 |
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Antisymmetric functions in higher dimensions Okay, maybe a nice definition of signed permuation of coordinates is a permuation matrix times a ${-1,1}$-diagonal matrix, and the signum is the determinant of that transform. |
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Apr 7 |
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Antisymmetric functions in higher dimensions That's interesting. Your functions are smooth, are they? And could you please define what a signed permuation and its signum mean? |
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Mar 18 |
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How should I understand “$A$ unless $B$”? That post is nicely written. Thanks! |
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Mar 13 |
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Derivative in complex analysis @anon: I am curious and my complex analysis is rusty, too. Why is $f$ constant? |
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Mar 7 |
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Which formula do I use to integrate $ \int {\sqrt{x^2 + 81} \over 2} \,dx $ In your final expression, the variable $x$ appears outside the integral, without any proper definition there. You should change this notation. |
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Mar 1 |
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First-order derivatives in differential forms calculus Because that is the way the Lie differential is defined. |
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Feb 22 |
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What is the theory of non-linear forms (as contrasted to the theory of differential forms)? I guess these non-linear forms are taken from David Bachmann's book "A Geometric Approach to Differential Forms", aren't they? |
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Jan 8 |
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Alternating forms tangential to a subspace. Corrected. Yes, thanks. |
